Modern hospitals utilize medical images from a variety of imaging devices such as, for example, a Computer Tomography (CT) scanner or a Magnetic Resonance Imaging (MRI) scanner producing volume datasets. The image data are then rendered for producing 2D images using a computer to enable medical professionals to view and diagnose the captured medical images.
Volume rendering is an important field of computer graphics and is of particular importance for medical applications for the rendering of volume image data sets generated by, for example, a CT or MRI scanner.
For rendering a volume dataset on a two dimensional display a view plane is defined, which depends on viewing parameters such as eye position, view direction, etc. For each point on the view plane a ray of sight is cast into the volume. Then the volume data are sampled at discrete sample points along each individual ray of sight. Each ray of sight accumulates color and transparency values along the ray of sight direction for each increment. The ray of sight is incremented until a maximum number of iterations has been reached, for example, the ray of sight travels until the back edge of the volume. Each increment of the ray includes a lighting calculation, typically using Phong shading comprising ambient, diffuse, and specular lighting calculations.
A major limitation of the employment of volume ray casting is its use of significant computational processing resources in particular when applied to large volume datasets of diagnostic quality medical images.
It would be desirable to provide a method for rendering a volume dataset using volume ray casting that substantially reduces the use of computational processing resources.